Presently, the DVD (Digital Versatile Disc), one of large-capacity optical discs, is available in the forms of: DVD-R (DVD-Recordable) capable of recording data; and DVD-RW (DVD-Rewritable), DVD-RAM (DVD-Random Access Memory), and the like capable of rewriting recorded data. Data recorded on DVD-R or DVD-RW cannot be reproduced on a reproducing apparatus, PC (personal computer), and the like compliant with only DVD-video formats because of format incompatibility. In order to allow the reproducing apparatus, PC, and the like to reproduce data recorded on the DVD-R or DVD-RW (hereafter referred to as the DVD-R/-RW), data recorded on the DVD-R/-RW needs to be converted into a specified format compliant with the DVD-video format. In order for the PC and the like to reproduce data recorded on the DVD-R/-RW, the data recorded on the DVD-R/-RW needs to comply with the Universal Disc Format (UDF) standard.
FIG. 1 shows a data structure of an optical disc that records data using a logical format compliant with the DVD-video format. As shown in FIG. 1A, an information recording surface on the optical disc compliant with the DVD-video format is divided into a lead-in area, a data zone, and a lead-out area from the innermost side. The data zone actually records intended real data.
The data zone is divided into three areas from the lead-in side: a UDF (Universal Disc Format) area A1, i.e., a file system area for describing a UDF bridge configuration; a VMG (Video Manager) area A2 as a DVD management information area; and a real time data recording area A3. The UDF area A1 and the VMG area A2 record information for managing video data recorded on the real time data recording area A3. The UDF area A1 is referred to as a first management information area. The VMG area A2 is referred to as a second management information area. The VMG area A2, i.e., the second management information area, corresponds to a file management system specific to the DVD-video format. The VMG area A2 records TOC (Table Of Contents), i.e., information to manage the whole of video data recorded in the real time data recording area A3. On the other hand, the UDF area A1, i.e., the first management information area, corresponds to a file management system specific to the PC and the like. The UDF area A1 uses a format such as UDF for compatibility with file systems for PC and the like to record information to manage the whole of video data recorded in the real time data recording area A3.
The real time data recording area A3 is a user area for recording real data such as motion pictures. As shown in FIG. 1B, motion pictures are recorded on the basis of VTS (Video Title Set). The VTS is referred to as a title. Up to 99 titles can be provided. As shown in FIG. 1C, the VTS comprises VTSI (Video Title Set Information), VTSM_VOBS (Video Object Set for the VTSM), VTSTT_VOBS (Video Object Set for Titles in a VTS), and VTSI_BUP (Backup of VTSI) from the beginning.
The VTSTT_VOBS records video data, i.e., actual data, according to the MPEG (Moving Picture Experts Group) 2 format. The VTSI records recording position information and the like, i.e., information for managing video data comprising actual data. The VTSM_VOBS records a title menu of the video data. The VTSM_VOBS is optional. The VTSI_BUP records backup data for VTSI. The VTSTT_VOBS comprises packetized data based on a specified amount. When data to be recorded comprises motion pictures, for example, the VTSTT_VOBS uses a chapter (CHP) as a reproduction unit and comprises a plurality of chapters (CHP) as shown in FIG. 1D.
When the PC or the like accesses an optical disc having the above-mentioned data structure, the UDF area A1 can be used to retrieve and reproduce an intended file. When a DVD player is used for reproduction, the VMG area A2 can be used to retrieve and reproduce an intended file.
There is available an Incremental Recording system (hereafter referred to as an INC system) or a Restricted Over Write system (hereafter referred to as an ROW system) as a recording system for writing motion pictures on such optical disc. The INC system is mainly used for DVD-R and the like and sequentially records motion pictures. The ROW system is mainly used for DVD-RW and the like and randomly records motion pictures. When data is recorded on an unrecorded area, even the ROW system needs to sequentially record motion pictures. The INC and ROW systems manage processes such as reservation on optical discs using an RMA (Recording Management Area) provided more inside than the lead-in area.
FIG. 2 shows a recording process according to the INC system. The INC system is defined to be able to write to up to three areas, i.e., each of these areas is referred to as Rzone. The RMA manages each Rzone area.
When recording a motion picture, the INC system first reserves the Rzone areas as shown in FIG. 2A. Here, the Rzone areas are reserved as follows. An area for Rzone 1 is defined so as to form the UDF area A1 and the VMG area A2, i.e., areas for recording the management information. An area for Rzone 2 is defined in the next unrecorded area to form the real time data recording area A3 so as to form the VTSI and the VTSM_VOBS of the first VTS. The remaining unrecorded area is defined to be an area for Invisible Rzone (Rzone 3). By reserving Rzone 1 and Rzone 2, the INC system ensures areas for recording the management information. It also ensures areas for forming the VTSI and the VTSM_VOBS of the first VTS.
The INC system sequentially records motion pictures from the beginning of the Invisible Rzone to form the VTSTT_VOBS comprising actual data. When a user's instruction completes recording of actual data for one VTS, the VTSI_BUP is recorded in succession to recording of the actual data as shown in FIG. 2B. Further, as shown in FIG. 2C, the system returns to the beginning and forms the VTSI and the VTSM_VOBS in the Rzone 2 to close it. In this manner, the INC system records one VTS on the optical disc.
FIG. 2D shows how the INC system records the next VTS successively. The system reserves the Rzone 3 in the remaining unrecorded area to ensure an area for the VTSI and the VTSM_VOBS and defines the Invisible Rzone. Then, as shown in FIG. 2E, the system records actual data to form the VTSTT_VOBS, and then forms the VTSI_BUP. As shown in FIG. 2F, the system forms the VTSI and the VTSM_VOBS in the previously ensured area. In this manner, successive VTS areas are recorded on the optical disc as shown in FIG. 2G. To successively record VTS, the INC system likewise defines an unrecorded area for successively recording VTS.
As mentioned above, the INC system successively records VTS's to form the real time data recording area A3 on the optical disc. Such optical disc requires format conversion by means of a closed session process and the like (hereafter referred to as a finalization process). Otherwise, the optical disc cannot be reproduced on a reproducing apparatus or the like that complies with only the DVD-video format. The following describes the finalization process with reference to FIG. 2H.
As shown in FIG. 2H, for example, the finalization process is used to form the UDF area A1 and the VMG area A2 in Rzone 1 on the optical disc. The lead-in area is formed on the innermost periphery. The lead-out area is formed on the outermost periphery. The finalization process can enable compatibility with read-only optical discs. To form the UDF area A1 and the VMG area A2, the system generates data to be recorded in the UDF area A1 and the VMG area A2 from data of the VTSI and the VTSM_VOBS in each VTS. The system records the generated data in Rzone 1 to close it.
FIG. 3 shows a recording process according to the ROW system. The ROW system performs padding to previously ensure areas for recording the lead-in area, the UDF area, the VMG area, and the VTSI and the VTSM_VOBS for the first VTS as shown in FIG. 3A. Here, the padding is a process to record dummy data such as NULL for ensuring areas.
After ensuring these areas, the ROW system sequentially records images as shown in FIG. 3B to form the VTSTT_VOBS comprising actual data. Upon completion of recording actual data for one VTS, the system then records the VTSI_BUP. The system performs the padding process to ensure areas for the VTSI and the VTSM_VOBS in the succeeding VTS. As shown in FIG. 3C, returning to the beginning, the system forms the VTSI and the VTSM_VOBS corresponding to the recording of this actual data. In this manner, the ROW system records one VTS on the optical disc.
To record the next VTS in succession, the ROW system, as shown in FIG. 3D, records actual data following the padding area formed by the immediately preceding VTS to form the VTSTT_VOBS and the VTSI_BUP. The padding process is performed to ensure areas for the VTSI and the VTSM_VOBS of the VTS to follow. As shown in FIG. 3E, the VTSI and the VTSM_VOBS are formed in succession. In this manner, the next VTS is recorded on the optical disc as shown in FIG. 3F. To further record the VTS, the ROW system likewise performs the padding process or the like to record the VTS successively.
As mentioned above, the ROW system successively records VTS's to form the real time data recording area A3 on the optical disc. Like the INC system, such optical disc requires format conversion by means of the finalization process and the like. Otherwise, the optical disc cannot be reproduced on a reproducing apparatus or the like that complies with only the DVD-video format. The following describes the finalization process with reference to FIG. 3G.
As shown in FIG. 3G, for example, the finalization process is used to form the UDF area and the VMG area in the area padded by the finalization process. The lead-in area is formed on the innermost periphery. The lead-out area is formed on the outermost periphery. The finalization process can enable compatibility with read-only optical discs.
FIG. 4 shows a data structure of the VMG in FIGS. 2H and 3G recorded by the finalization process. FIG. 4 represents the data structure of menu information (hereafter referred to as a main menu) for selecting each title (each VTS).
The VMG comprises VMGI (Video Manager Information) and VMGM_VOBS (Video Object Set for the VMG menu). The VMGI records a group of VMGM_PGCI (VMG Menu Program Chain Information), i.e., link information to each VTS menu. This information takes effect when selected between menu pages or from the main menu. Each VMGM_VOBS comprises a plurality of cells each of which corresponds to each main menu screen page. The cell records the following images in the MPEG (Motion Picture Experts Group) format: a menu screen background, a menu title, a thumbnail (hereafter referred to as a VTS thumbnail) created from a representative image of each VTS, a previous page button, a next page button, and the like. Further, the cell includes NV_PCK comprising PCI and DSI. The PCI includes HLI (Highlight Information). The HLI records information such as a VTS thumbnail position, a button position, a highlight color, highlight movement when a four-direction button is pressed, and the like.
For example, a main menu screen in FIG. 5 can be realized by appropriately recording the VMG having the above-mentioned structure. A menu key is used to call the menu screen. The four-direction key is used to move a highlight. An execution key is centered on the four-direction key and can be used to select one VTS thumbnail. The execution key can be also used to call the VTS menu (to be described) or switch between menu pages. Selecting the next page button displays the next main menu. Selecting the previous page button displays the most recent main menu. In the example of FIG. 5, one main menu contains six VTS thumbnails, but is not limited thereto.
FIG. 6 shows a data structure of the VTS in FIGS. 2C and 3C recorded when the VTS is closed. FIG. 6 shows the data structure of information about a menu (hereafter referred to as a VTS menu) for selecting each CHP included in the VTS.
The VTS comprises VTSI, VTSM_VOBS, VTSTT_VOBS, and VTSI_BUP. The VTSI records a group of VTSM_PGCI (VTS Menu Program Chain Information), i.e., link information to each CHP. This information takes effect when selected between menu pages or from the VTS menu. Each VTSM_VOBS comprises a plurality of cells each of which corresponds to each VTS menu screen page. The cell records the following images in the MPEG format: a menu screen background, a menu title, a thumbnail (hereafter referred to as a CHP thumbnail) created from a representative image of each CHP (to be described), a previous page button, a next page button, and the like. Further, the cell includes NV_PCK comprising PCI and DSI. The PCI includes HLI (Highlight Information). The HLI records information such as a CHP thumbnail position, a button position, a highlight color, highlight movement when a four-direction button is pressed, and the like.
For example, a VTS menu screen shown in FIG. 7 can be realized by appropriately recording the VTS having the above-mentioned structure. As mentioned above, the VTS menu can be selected from the main menu to call a VTS menu screen as shown in FIG. 7. The four-direction key is used to move a highlight on the called VTS menu screen. The execution key at the center of the four-direction key can be used to select one CHP thumbnail, reproduce or display a selected chapter (CHP), or switch between menu pages. Selecting the next page button displays the next VTS menu. Selecting the previous page button displays the immediately preceding VTS menu. In FIG. 7, one VTS menu contains six CHP thumbnails, but may be configured as described in Japanese Patent Publication No. 2875231.
As mentioned above, the DVD-video format has a limitation of up to 99 titles (VTS's) capable of being recorded on an optical disc. When one scene per title is recorded in compliance with the DVD-video format, only up to 99 scenes can be recorded on one optical disc. For example, let us assume that one scene is recorded five or six seconds. Then, one optical disc can just record scenes up to approximately eight minutes.
The DVD-video format is specified to be able to divide one title into 99 scenes or chapters (CHP). When data is recorded based on one scene per chapter, one optical disc can record 99×99=9801 scenes.
As shown in FIGS. 5 and 7, the DVD-video format creates menus in two layers independently of user's intentions. A scene (CHP) is divided into a plurality of VTS menus. In order to select an intended scene (CHP), the user first selects a VTS thumbnail from the main menu in FIG. 5 to call the VTS menu. The user then needs to select an intended CHP from the called VTS menu as shown in FIG. 7.